Omnipolyphilins A and B: Chlorinated Cyclotetrapeptides and Naphtho-α-pyranones from the Plant Nematode-Derived Fungus Polyphilus sieberi

Chemical exploration for two isolates of the recently described ascomycete species Polyphilus sieberi, derived from the eggs of the plant parasitic nematode Heterodera filipjevi, afforded the identification of many compounds that belong to various metabolite families: two previously undescribed chlorinated cyclotetrapeptides, omnipolyphilins A (1) and B (2), one new pyranonaphthoquinone, ventiloquinone P (3), a 6,6'-binaphto-α-pyranone dimer, talaroderxine D (4) in addition to nine known metabolites (5-13) were isolated from this biocontrol candidate. All isolated compounds were characterized by comprehensive 1D, 2D NMR, and HR-ESI-MS analyses. The absolute configurations of the cyclotetrapeptides were determined by a combination of advanced Marfey's method, ROE correlation aided by conformational analysis, and TDDFT-ECD calculations, while ECD calculations, Mosher's method, and experimental ECD spectra were used for ventiloquinone P (3) and talaroderxine D (4). Among the isolated compounds, talaroderxine D (4) showed potent antimicrobial activities against Bacillus subtilis and Staphylococcus aureus with MIC values of 2.1 and 8.3 μg mL-1, respectively. Additionally, promising inhibitory effects on talaroderxine D (4) against the formation of S. aureus biofilms were observed up to a concentration of 0.25 μg mL-1. Moreover, ophiocordylongiiside A (10) showed activity against the free-living nematode Caenorhabditis elegans.

Lachnuoic Acids A-F: Ambuic Acid Congeners from a Saprotrophic Lachnum Species

Chemical prospection of an extract derived from a saprotrophic fungus Lachnum sp. IW157 resulted in the isolation and characterization of six unprecedentedly reported ambuic acid analogues named lachnuoic acids A-F (1-6). Chemical structures of 1-6 were determined based on comprehensive 1D and 2D NMR spectroscopic analyses together with HR-ESI-MS spectrometry. The relative configurations of 1-3 were defined by ROESY spectroscopic analyses while their absolute configurations were unambiguously determined by Mosher's esters method. All isolated compounds were subjected to cytotoxic, antimicrobial, antibiofilm and nematicidal activity assays where only lachnuoic acid A (1) revealed potent antimicrobial activity against Staphylococcus aureus and Bacillus subtilis at MIC values of 16.6 and 8.3 μg/mL, respectively.

Cytotoxic naphtho- and benzofurans from an endophytic fungus Epicoccum nigrum Ann-B-2 associated with Annona squamosa fruits

Chemical exploration of the total extract derived from Epicoccum nigrum Ann-B-2, an endophyte associated with Annona squamosa fruits, afforded two new metabolites, epicoccofuran A (1) and flavimycin C (2), along with four known compounds namely, epicocconigrone A (3), epicoccolide B (4), epicoccone (5) and 4,5,6-trihydroxy-7-methyl-1,3-dihydroisobenzofuran (6). Structures of the isolated compounds were elucidated using extensive 1D and 2D NMR along with HR-ESI-MS. Flavimycin C (2) was isolated as an epimeric mixture of its two diastereomers 2a and 2b. The new compounds 1 and 2 displayed moderate activity against B. subtilis, whereas compounds (2, 3, 5, and 6) showed significant antiproliferative effects against a panel of seven different cancer cell lines with IC50 values ranging from 1.3 to 12 µM.

Cytotoxic Polyhydroxy-Isoprenoids from Neodidymelliopsis negundinis

Fungal-derived natural products continue to play a pivotal role in the discovery of drug agents for human, veterinary, and general agricultural use. The fungus Neodidymelliopsis negundinis presents a significant saprobic ascomycete whose metabolites remained hitherto unstudied. Herein we report the isolation of eight unprecedented secondary metabolites named neodidymelliosides A and B (1 and 2), neodidymelliol A (3), and neodidymellioic acids A-E (4-8) produced by the submerged cultures of the fungus. Compound 1 proved to be the most active compound, with IC50 values ranging between 4.8 and 8.8 μM against KB3.1 (cervix), PC-3 (prostate), MCF-7 (breast), SKOV-3 (ovary), A431 (skin), and A549 (lung) cell lines. Compound 1 revealed significant inhibition of Staphylococcus aureus and Candida albicans biofilms.

Bioprospection of Tenellins Produced by the Entomopathogenic Fungus Beauveria neobassiana

Fungi are known as prolific producers of bioactive secondary metabolites with applications across various fields, including infectious diseases, as well as in biological control. However, some of the well-known species are still underexplored. Our current study evaluated the production of secondary metabolites by the entomopathogenic fungus Beauveria neobassiana from Thailand. The fermentation of this fungus in a liquid medium, followed by preparative high-performance liquid chromatography (HPLC) purification, resulted in the isolation of a new tenellin congener, namely pretenellin C (1), together with five known derivatives (2-6). Their chemical structures were elucidated by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy in combination with high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). We evaluated the antimicrobial and cytotoxic activities from all isolated compounds, as well as their inhibitory properties on biofilm formation by Staphylococcus aureus. Generally, tenellins displayed varying antibiofilm and cytotoxic effects, allowing us to propose preliminary structure-activity relationships (SARs). Among the tested compounds, prototenellin D (2) exhibited the most prominent antibiofilm activity, while its 2-pyridone congener, tenellin (4), demonstrated potent cytotoxic activity against all tested cell lines. Given the fact that the biological activities of the tenellins have so far been neglected in the past, our study could provide a good starting point to establish more concise structure-activity relationships in the near future.

Cytotoxic and antimicrobial mycophenolic acid derivatives from an endophytic fungus Penicillium sp. MNP-HS-2 associated with Macrozamia communis

Macrozamia communis and its associated endophytic fungi are untapped sources of bioactive metabolites with great potential for medicinal exploitation. Chemical investigation of the mycelial extract derived from an endophytic fungus Penicillium sp. MNP-HS-2 associated with M. communis fruit afforded four mycophenolic acid derivatives recognized as previously undescribed natural products (1-4), together with nine known metabolites (5-13). Chemical structures of isolated compounds were determined based on extensive spectroscopic analyses, including 1D/2D NMR and HRESIMS. The absolute stereochemistry of alternatain E (1) was unambiguously established by comparing its experimental and calculated time-dependent density functional theory electronic circular dichroism spectra (TDDFT-ECD). All isolated compounds were assessed for their antimicrobial and cytotoxic activities, where mycophenolic acid methyl ester (7), displayed significant cytotoxic activity against seven different cell lines with IC50 values in the low micromolar to nanomolar range. Mycophenolene A (3) exhibited significant antibacterial activity against Staphylococcus aureus (MIC = 2.1 μg/mL).

Promising anti-Helicobacter pylori and anti-inflammatory metabolites from unused parts of Phoenix dactylifera CV 'Zaghloul': in vitro and in silico study

CONTEXT

Date palm waste is an agricultural waste that accumulates in massive amounts causing serious pollution and environmental problems.

OBJECTIVES

Date palm trees, Phoenix dactylifera Linn CV 'Zaghloul' (Arecaceae) grown in Egypt, leave behind waste products that were investigated to produce compounds with anti-Helicobacter pylori and anti-inflammatory activities.

MATERIALS AND METHODS

Chromatographic workup of P. dactylifera aqueous methanol extract derived from fibrous mesh and fruit bunch (without fruit) afforded a new sesquiterpene lactone derivative, phodactolide A (1), along with ten known compounds (2-11), primarily identified as polyphenols. Chemical structures were unambiguously elucidated based on mass and 1D/2D NMR spectroscopy. All isolated compounds were assessed for their activities against H. pylori using broth micro-well dilution method and clarithromycin as a positive control. The anti-inflammatory response of isolated compounds was evaluated by inhibiting cyclooxygenase-2 enzyme using TMPD Assay followed by an in silico study to validate their mechanism of action using celecoxib as a standard drug.

RESULTS

Compounds 4, 6 and 8-10 exhibited potent anti-H. pylori activity with MIC values ranging from 0.48 to 1.95 µg/mL that were comparable to or more potent than clarithromycin. For COX-2 inhibitory assay, 4, 7 and 8 revealed promising activities with IC₅₀ values of 1.04, 0.65 and 0.45 μg/mL, respectively. These results were verified by molecular docking studies, where 4, 7 and 8 showed the best interactions with key amino acid residues of COX-2 active site.

CONCLUSION

The present study characterizes a new sesquiterpene lactone and recommends 4 and 8 for future in vivo studies as plausible anti-ulcer remedies.

Neurite Outgrowth-Inducing Drimane-Type Sesquiterpenoids Isolated from Cultures of the Polypore Abundisporus violaceus MUCL 56355

Abundisporin A (1), together with seven previously undescribed drimane sesquiterpenes named abundisporins B-H (2-8), were isolated from a polypore, Abundisporus violaceus MUCL 56355 (Polyporaceae), collected in Kenya. Chemical structures of the isolated compounds were elucidated based on exhaustive 1D and 2D NMR spectroscopic measurements and supported by HRESIMS data. The absolute configurations of the isolated compounds were determined by using Mosher's method for 1-4 and TDDFT-ECD calculations for 4 and 5-8. None of the isolated compounds exhibited significant activities in either antimicrobial or cytotoxicity assays. Notably, all of the tested compounds demonstrated neurotrophic effects, with 1 and 6 significantly increasing outgrowth of neurites when treated with 5 ng/mL NGF.

Diaporphasines E and F: New Polyketides from the Saprotrophic Fungus Lachnum sp. IW157 Growing on the Reed Grass Phragmites communis

Chemical investigation for the mycelial extract of a saprotrophic fungus Lachnum sp. IW157 growing on the common reed grass Phragmites communis afforded the identification of two polyketide metabolites diaporphasines E (1) and F (2). Chemical structures of isolated compounds were unambiguously elucidated based on extensive 1D and 2D NMR spectral analyses in addition to their high-resolution mass spectrometry. The isolated compounds were assessed for their cytotoxicity and antimicrobial and biofilm inhibitory activities. While compound 1 revealed potent cytotoxicity against the tested cell lines L929 and KB3.1 with IC50 values of 0.9 and 3.7 μM, respectively, compound 2 exhibited moderate effects on the formation of S. aureus biofilms at 31.25 μg/mL.

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

Chemical exploration of solid-state cultures of the polypore Fomitopsis carnea afforded two new C31 lanostane-type triterpenoid glycosides, forpiniosides B (1) and C (2) together with two known derivatives, namely 3-epipachymic acid (3) and (3α,25S)-3-O-malonyl-23-oxolanost-8,24(31)-dien-26-oic acid (4). The structures of the isolated compounds were established based on HRESIMS and extensive 1D and 2D NMR experiments. All the isolated compounds were assessed for their antimicrobial and cytotoxic activities. Among the tested compounds, forpinioside B (1) exhibited significant antimicrobial activity against Staphylococcus aureus and Bacillus subtilis at MIC values comparable to gentamycin and oxytetracycline (positive controls), respectively.

Bioactive Naphtho-α-Pyranones from Two Endophytic Fungi of the Genus Polyphilus

In the course of our survey to study the metabolic potential of two species of a new helotialean genus Polyphilus, namely P. frankenii and P. sieberi, their crude extracts were obtained using different cultivation techniques, which led to the isolation and characterization of two new naphtho-α-pyranone derivatives recognized as a monomer (1) and its 6,6'-homodimer (2) together with two known diketopiperazine congeners, outovirin B (3) and (3S,6S)-3,6-dibenzylpiperazine-2,5-dione (4). The structures of isolated compounds were determined based on extensive 1D and 2D NMR and HRESIMS. The absolute configuration of new naphtho-α-pyranones was determined using a comparison of their experimental ECD spectra with those of related structural analogues. 6,6'-binaphtho-α-pyranone talaroderxine C (2) exhibited potent cytotoxic activity against different mammalian cell lines with IC50 values in the low micromolar to nanomolar range. In addition, talaroderxine C unveiled stronger antimicrobial activity against Bacillus subtilis rather than Staphylococcus aureus with MIC values of 0.52 µg mL-1 (0.83 µM) compared to 66.6 µg mL-1 (105.70 µM), respectively.

Hericioic Acids and Hericiofuranoic Acid; Neurotrophic Agents from Cultures of the European Mushroom Hericium flagellum

Neurodegenerative diseases are currently posing huge social, economic, and healthcare burdens among the aged populations worldwide with few and only palliative treatment alternatives available. Natural products continue to be a source of a vast array of potent neurotrophic molecules that could be considered as drug design starting points. The present study reports eight new isoindolinone and benzofuranone derivatives, for which we propose the trivial names, hericioic acids A-G (1-7) and hericiofuranoic acid (8), which were isolated from a solid culture (using rice as substrate) of the rare European edible mushroom Hericium flagellum. The chemical structures of these compounds were determined based on extensive 1D and 2D NMR spectroscopy along with HRESIMS analyses. The isolated compounds were assessed for their neurotrophic activity in rat pheochromocytoma cells (PC-12) to promote neurite outgrowth on 5 ng NGF supplementation; all the compounds increased neurite outgrowths, with compounds 3, 4, and 8 exhibiting the strongest effects.

Lasiodipline G and other diketopiperazine metabolites produced by Lasiodiplodia chiangraiensis

Lasiodiplodia fungi are known to colonize plants as both pathogens and/or endophytes; hence, they can be exploited for their beneficial roles. Many compound classes from the genus have exhibited their potential biotechnological applications. Herein, we report two new metabolites 1 and 2 together with three known cyclo-(D-Ala-D-Trp) (3), indole-3-carboxylic acid (4) and a cyclic pentapeptide clavatustide B (5), isolated from the submerged cultures of a recently described species L. chiangraiensis. Chemical structures of the isolated compounds were determined by extensive NMR spectroscopic analyses together with HRESIMS. The absolute configurations of the new compounds were established based on comparing experimental and calculated time-dependent density functional theory circular dichroism (TDDFT-ECD) spectra. Compound 1 exhibited significant cytotoxic activities against an array of cell lines with IC₅₀ values of 2.9-12.6 μM, as well as moderate antibacterial effects.

Pro-Apoptotic Activity of the Marine Sponge Dactylospongia elegans Metabolites Pelorol and 5-epi-Ilimaquinone on Human 501Mel Melanoma Cells

The natural environment represents an important source of drugs that originates from the terrestrial and, in minority, marine organisms. Indeed, the marine environment represents a largely untapped source in the process of drug discovery. Among all marine organisms, sponges with algae represent the richest source of compounds showing anticancer activity. In this study, the two secondary metabolites pelorol (PEL) and 5-epi-ilimaquinone (EPI), purified from Dactylospongia elegans were investigated for their anti-melanoma activity. PEL and EPI induced cell growth repression of 501Mel melanoma cells in a concentration- and time-dependent manner. A cell cycle block in the G1 phase by PEL and EPI was also observed. Furthermore, PEL and EPI induced significant accumulation of DNA histone fragments in the cytoplasmic fraction, indicating a pro-apoptotic effect of both compounds. At the molecular level, PEL and EPI induced apoptosis through the increase in pro-apoptotic BAX expression, confirmed by the decrease in its silencing miR-214-3p and the decrease in the anti-apoptotic BCL-2, MCL1, and BIRC-5 mRNA expression, attested by the increase in their silencing miRNAs, i.e., miR-193a-3p and miR-16-5p. In conclusion, our data indicate that PEL and EPI exert cytotoxicity activity against 501Mel melanoma cells promoting apoptotic signaling and inducing changes in miRNA expression and their downstream effectors. For these reasons could represent promising lead compounds in the anti-melanoma drug research.

Anti‐Inflammatory, Antiallergic and COVID‐19 Main Protease (M pro ) Inhibitory Activities of Butenolides from a Marine‐Derived Fungus Aspergillus costaricaensis

Amid the current COVID‐19 pandemic, the emergence of several variants in a relatively high mutation rate (twice per month) strengthened the importance of finding out a chemical entity that can be potential for developing an effective medicine. In this study, we explored ethyl acetate (EtOAc) extract of a marine‐derived fungus Aspergillus cosatricaensis afforded three butenolide derivatives, butyrolactones I, VI and V (1–3), two naphtho‐γ‐pyrones, TMC‐256 A1 (4) and rubrofusarin B (5) and methyl p‐hydroxyphenyl acetate (6). Structure identification was unambiguously determined based on exhaustive spectral analyses including 1D/2D NMR and mass spectrometry. The isolated compounds (1–6) were assessed for their in vitro anti‐inflammatory, antiallergic, elastase inhibitory activities and in silico SARS‐CoV‐2 main protease (M^pro). Results exhibited that only butenolides (1 and 2) revealed potent activities similar to or more than reference drugs unlike butyrolactone V (3) suggesting them as plausible chemical entities for developing lead molecules.

Penicacids H-J, three new mycophenolic acid derivatives from the marine-derived fungus Rhizopus oryzae

Chemical investigation of secondary metabolites in crude methanol extract of a solid rice medium of a marine-derived fungus, Rhizopus oryzae, has enriched the metabolic profile of this genus by affording three mycophenolic acid derivatives recognized as new fungal metabolites trivially named as penicacids H–J (1–3), along with two known naphtho-γ-pyrone dimers, asperpyrone A (4) and dianhydroaurasperone C (5). Structure elucidation of isolated compounds was unambiguously determined based on extensive 1D and 2D NMR spectroscopic analyses together with comparing coupling constant and optical rotation values with those reported for related congeners in literature. All isolated compounds were assessed for their antibacterial activity against four different bacterial microorganisms and they revealed moderate to weak activities with minimum inhibitory concentration (MIC) values ranging from 62.5 to 250 μg mL⁻¹.

Penicacids H–J (1–3), three new natural MPA derivatives, were purified from a marine-derived fungus, Rhizopus oryzae, together with two known naphtho-γ-pyrone dimers, asperpyrone A (4) and dianhydroaurasperone C (5).

Anti-Inflammatory, Antiallergic, and COVID-19 Main Protease (Mpro) Inhibitory Activities of Butenolides from a Marine-Derived Fungus Aspergillus terreus

In December 2020, the U.K. authorities reported to the World Health Organization (WHO) that a new COVID-19 variant, considered to be a variant under investigation from December 2020 (VUI-202012/01), was identified through viral genomic sequencing. Although several other mutants were previously reported, VUI-202012/01 proved to be about 70% more transmissible. Hence, the usefulness and effectiveness of the newly U.S. Food and Drug Administration (FDA)-approved COVID-19 vaccines against these new variants are doubtfully questioned. As a result of these unexpected mutants from COVID-19 and due to lack of time, much research interest is directed toward assessing secondary metabolites as potential candidates for developing lead pharmaceuticals. In this study, a marine-derived fungus Aspergillus terreus was investigated, affording two butenolide derivatives, butyrolactones I (1) and III (2), a meroterpenoid, terretonin (3), and 4-hydroxy-3-(3-methylbut-2-enyl)benzaldehyde (4). Chemical structures were unambiguously determined based on mass spectrometry and extensive 1D/2D NMR analyses experiments. Compounds (1-4) were assessed for their in vitro anti-inflammatory, antiallergic, and in silico COVID-19 main protease (Mpro) and elastase inhibitory activities. Among the tested compounds, only 1 revealed significant activities comparable to or even more potent than respective standard drugs, which makes butyrolactone I (1) a potential lead entity for developing a new remedy to treat and/or control the currently devastating and deadly effects of COVID-19 pandemic and elastase-related inflammatory complications.

Anti-inflammatory, antiallergic and COVID-19 protease inhibitory activities of phytochemicals from the Jordanian hawksbeard: identification, structure–activity relationships, molecular modeling and impact on its folk medicinal uses

On Wednesday 11th March, 2020, the world health organization (WHO) announced novel coronavirus (COVID-19, also called SARS-CoV-2) as a pandemic.

Verification of the anti-inflammatory activity of the polyphenolic-rich fraction of Araucaria bidwillii Hook. using phytohaemagglutinin-stimulated human peripheral blood mononuclear cells and virtual screening

ETHNOPHARMACOLOGICAL RELEVANCE

Araucaria bidwillii Hook., the bunya pine, is an evergreen plant belonging to family Araucariaceae. Traditionally, its leaves and oleoresins have been used as herbal remedies to alleviate pain and inflammation. Based upon the frequent adverse effects accompanying synthetic anti-inflammatory drugs, this study will assess the anti-inflammatory activity of both the total methanol extract and the polyphenolic-rich fraction of A. bidwillii leaves.

MATERIALS AND METHODS

The anti-inflammatory activity was assessed in vitro using phytohaemagglutinin-stimulated human peripheral blood mononuclear cells (PBMCs). Isolation of the major compounds was conducted using various chromatographic techniques. Molecular modelling studies are performed on tumor necrosis factor-α (TNF-α), cyclooxygenase-II (COX-II) and 5-lipooxygenase (5-LOX).

RESULTS

Both the total methanol extract of Araucaria bidwillii leaves and its fraction revealed a dose-dependent manner in lowering the levels of IL-1β, IL-6 and TNF-α with an equivalent activity to that of indomethacin. In addition, the phytochemical investigation of the polyphenolic-rich fraction results in identification of agathisflavone-4',7''-dimethyl ether (1), 7-O-methyl-6-hydroxyapigenin (2) and 4',4'-di-O-methylamentoflavone (3) as the main components. In silico molecular modelling showed that agathisflavone-4',7''-dimethyl ether (1) exhibited the fittest binding in TNF-α active sites, while 7-O-methyl-6-hydroxyapigenin (2) showed the highest inhibition in COX-II whereas 4',4'-di-O-methylamentoflavone (3) is the most potent 5-LOX inhibitor.

CONCLUSION

Thus, the leaves of Araucaria bidwillii could afford a potent anti-inflammatory agent that effectively ameliorates inflammation and its related hazards. This in turn consolidates the fact of using the leaves of Araucaria bidwillii to sooth inflammation in traditional medicine.

Polyphenols from Tamarix nilotica: LC⁻ESI-MSn Profiling and In Vivo Antifibrotic Activity

Tamarix nilotica (Ehrenb.) Bunge (Tamaricaceae), an indigenous plant to the Middle East region, is well-known as a medicinal plant for treating many human ailments. The current study aimed at exploring the polyphenol profile of the alcohol soluble fraction of aqueous T. nilotica extract, assessing its in vivo antifibrotic activity and the possible underlying mechanism, to unravel the impact of quantitative difference of sulphated polyphenols content on the antifibrotic activity of T. nilotca grown in two different habitats. Polyphenol profiling of T. nilotica extracts was performed using HPLC-HRESI-QTOF-MS-MS. The major polyphenol components included sulphated flavonoids, phenolic acids and free aglycones. The antifibrotic activity was evaluated through carbon tetrachloride-induced liver fibrosis in rats. Biochemical evaluations revealed that both fractions ameliorated the increased levels of hepatic aminotransferases, lipid peroxidation, hydroxyproline, α-smooth muscle actin (α-SMA), tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) and nuclear factor kappa B (NF-κB). Moreover, both fractions reduced catalase activity (CAT) and enhanced hepatic glutathione (GSH) content. Histopathological imaging undoubtedly confirmed such results. In conclusion, the T. nilotica polyphenol-rich fraction exhibited potential antifibrotic activity in rats. Significant alterations in GSH levels were recorded based on the sulphated polyphenol metabolite content.

Chemotaxonomic Diversity of Three Ficus Species: Their Discrimination Using Chemometric Analysis and Their Role in Combating Oxidative Stress

BACKGROUND

Genus Ficus (Moraceae) constitutes more than 850 species and about 2000 varieties and it acts as a golden mine that could afford effective and safe remedies combating many health disorders.

OBJECTIVES

Discrimination of Ficus cordata, Ficus ingens, and Ficus palmata using chemometric analysis and assessment of their role in combating oxidative stress.

MATERIALS AND METHODS

Phytochemical profiling of the methanol extracts of the three Ficus species and their successive fractions was performed using high-performance liquid chromatography/electrospray ionization mass spectrometry. Their discrimination was carried out using the obtained spectral data applying chemometric unsupervised pattern-recognition techniques, namely, principal component analysis and hierarchical cluster analysis. In vitro hepatoprotective and antioxidant evaluation of the samples was performed using human hepatocellular carcinoma cells challenged by carbon tetrachloride (CCl4).

RESULTS

Altogether, 22 compounds belonging to polyphenolics, flavonoids, and furanocoumarins were identified in the three Ficus species. Aviprin is the most abundant compound in F. cordata while chlorogenic acid and psoralen were present in high percentages in F. ingens and F. palmata, respectively. Chemometric analyses showed that F. palmata and F. cordata are more closely related chemically to each other rather than F. ingens. The ethyl acetate fractions of all the examined species showed a marked hepatoprotective efficacy accounting for 54.78%, 55.46%, and 56.42% reduction in serum level of alanine transaminase and 56.82%, 54.16%, and 57.06% suppression in serum level of aspartate transaminase, respectively, at 100 μg/mL comparable to CCl4-treated cells.

CONCLUSION

Ficus species exhibited a no table antioxidant and hepatoprotective activity owing to their richness in polyphenolics and furanocoumarins.

SUMMARY

Ficus cordata, Ficus ingens, and Ficus palmata were analyzed using high-performance liquid chromatography/electrospray ionization mass spectrometry that revealed their richness with polyphenolics and furanocoumarinsDiscrimination of the three species was performed using spectral data coupled with chemometrics that showed that F. palmata and F. cordata are chemically related to each other rather than F. ingensIn vitro hepatoprotective and antioxidant evaluation was performed using human hepatocellular carcinoma cells. The ethyl acetate fractions of all the examined species showed a marked hepatoprotective efficacyFicus species exhibited notable activities due to polyphenolics and furanocoumarins. Abbreviations used: ALT: Alanine transaminase, AST: Aspartate transaminase, CCl4: Carbon tetrachloride, DMEM: Dulbecco's Modified Eagle's medium, DMSO: Dimethyl sulfoxide, EDTA: Ethylenediaminetetraacetic acid, FBS: Fetal bovine serum, FCA: Ficus cordata remaining aqueous fraction, FCB: Ficus cordata n-butanol fraction, FCE: Ficus cordata ethyl acetate fraction, FCP: Ficus cordata petroleum ether fraction, FCT: Ficus cordata total methanol extract, FIA: Ficus ingens remaining aqueous fraction, FIB: Ficus ingens n-butanol fraction, FIE: Ficus ingens ethyl acetate fraction, FIP: Ficus ingens petroleum ether fraction, FIT: Ficus ingens total methanol extract, FPA: Ficus palmata remaining aqueous fraction, FPB: Ficus palmata n-butanol fraction, FPE: Ficus palmata ethyl acetate fraction, FPP: Ficus palmata petroleum ether fraction, FPT: Ficus palmata total methanol extract, GSH: Reduced glutathione, HepG2 cells: Human hepatocellular carcinoma, HPLC-ESI-MS: High-performance liquid chromatography/electrospray ionization mass spectrometry, and SOD: Superoxide dismutase.

Antihyperglycaemic activity of the methanol extract from leaves of Eremophila maculata (Scrophulariaceae) in streptozotocin-induced diabetic rats

OBJECTIVES

This study was designed to evaluate the antihyperglycaemic activity of the methanol leaf extract of Eremophila maculata (EMM) both in vitro and in vivo.

METHODS

The antihyperglycaemic activity was assessed in vitro using differentiated 3T3-L1 adipocytes, whereas in-vivo effect was evaluated in streptozotocin-induced diabetic rats. Chemical profiling of EMM was done using LC-ESI-MS techniques. Molecular modelling experiments of the identified compounds were performed using C-Docker protocol.

KEY FINDINGS

Eremophila maculata slightly enhanced cellular glucose uptake and utilization in vitro by 3.92% relative to the untreated control. A stronger in-vivo effect was observed for EMM and its dichloromethane fraction. A pronounced elevation in serum insulin by 88.89 and 66.67%, respectively, accompanied by an apparent decline in fasting blood glucose (FBG) level by 65.60 and 70.37% comparable to streptozotocin-induced diabetic rats was observed. This effect was stronger than that of the reference drug glibenclamide (GLB). Chemical profiling of EMM revealed that leucoseptoside A, verbascoside, syringaresinol-4-O-β-D-glucopyranoside, pinoresinol-4-O-β-D-glucopyranoside and pinoresinol-4-O-[6″-O-(E)-feruloyl]-β-D-glucopyranoside are the major compounds. Molecular modelling showed that martynoside, verbascoside and phillygenin exhibited the highest inhibition to human pancreatic α-amylase (HPA), maltase glucoamylase (MGAM) and aldose reductase (AR), respectively.

CONCLUSION

Eremophila maculata offers an interesting relatively safer antihyperglycaemic candidate comparable to synthetic analogues.

Cytotoxic effects of the anthraquinone derivatives 1'-deoxyrhodoptilometrin and (S)-(-)-rhodoptilometrin isolated from the marine echinoderm Comanthus sp

We investigated cytotoxic effects of the anthraquinone derivatives 1'-deoxyrhodoptilometrin (SE11) and (S)-(-)-rhodoptilometrin (SE16) isolated from the marine echinoderm Comanthus sp. in two tumor cell lines (C6 glioma, Hct116 colon carcinoma). Both compounds showed cytotoxic effects, with SE11 [IC₅₀-value (MTT assay): 13.1 µM in Hct116 cells] showing a higher potency to induce apoptotic and necrotic cell death. No generation of oxidative stress was detectable (DCF assay), and also no modulation of Nrf2/ARE and NFκB signaling could be shown. Investigation of 23 protein kinases associated with cell proliferation, survival, metastasis, and angiogenesis showed that both compounds were potent inhibitors of distinct kinases, e.g., IGF1-receptor kinase, focal adhesion kinase, and EGF receptor kinase with SE11 being a more potent compound (IC₅₀ values: 5, 18.4 and 4 µM, respectively). SE11 caused a decrease in ERK phosphorylation which may be a consequence of the inhibition of EGF receptor kinase by this compound. Since an inhibition of the EGF receptor/MAPK pathway is an important target for diverse cytostatic drugs, we suggest that the anthraquinone derivative 1'-deoxyrhodoptilometrin (SE11) may be an interesting lead structure for the development of new anticancer drugs.

Bioactive terpenes from marine-derived fungi

Marine-derived fungi continue to be a prolific source of secondary metabolites showing diverse bioactivities. Terpenoids from marine-derived fungi exhibit wide structural diversity including numerous compounds with pronounced biological activities. In this review, we survey the last five years’ reports on terpenoidal metabolites from marine-derived fungi with particular attention on those showing marked biological activities.

3-O-trans-Caffeoylisomyricadiol: A New Triterpenoid from Tamarix nilotica Growing in Saudi Arabia

A detailed chemical study of the aerial parts of Tamarix nilotica (Tamaricaceae) from Saudi Arabia led to the isolation of a new pentacyclic triterpenoid, 3-O-trans-caffeoylisomyricadiol, in addition to nine known compounds. The structures of all isolated compounds were unambiguously elucidated by 1D, 2D NMR, and mass spectrometry. In the radical scavenging (DPPH) assay, 3-O-trans-caffeoylisomyricadiol exhibited potent antioxidant activity with an IC50 value of 3.56 μM, while that for quercetin (standard antioxidant) was 5.72 μM

A new cytotoxic steroid from co-fermentation of two marine alga-derived micro-organisms

Bioactivity-guided chemical investigation of a co-culture of marine-derived micro-organisms has yielded one new steroid, 7β-hydroxycholesterol-1β-carboxylic acid (1) with an unprecedented carboxylic acid group at C-1, together with three known steroidal metabolites (2-4). The chemical structures and stereochemistry of the isolated compounds were unambiguously determined based on extensive 1D, 2D NMR and HR-ESI-MS measurements. The isolated compounds were assessed for their cytotoxic activity against four different human tumour cell lines K562 (leukaemia), HCT116 (colon), A2780 (ovary) and its cisplatin-resistant mutant (A2780 CisR), and they revealed moderate activities with IC50 values ranging from 10.0 to 100.0 μM.

Psychrophilin E, a new cyclotripeptide, from co-fermentation of two marine alga-derived fungi of the genus Aspergillus

Chemical investigation of the mycelial extract of a mixed culture of two marine alga-derived fungal strains of the genus Aspergillus has yielded one new cyclotripeptide, psychrophilin E (1), the recently reported oxepin-containing alkaloids, protuboxepin A (2) and oxepinamide E (3), together with three other polyketide derivatives (4-6). The chemical structure and relative and absolute configurations of psychrophilin E (1) were unambiguously established based on HRMS, 1D, 2D NMR and chiral-phase HPLC analysis of its hydrolysate. All the isolated compounds were assessed for their anti-proliferative activity against four different human cancer cell lines and some of them revealed selective activities.

Bioactive sesterterpenes and triterpenes from marine sponges: occurrence and pharmacological significance

Marine ecosystems (>70% of the planet's surface) comprise a continuous resource of immeasurable biological activities and immense chemical entities. This diversity has provided a unique source of chemical compounds with potential bioactivities that could lead to potential new drug candidates. Many marine-living organisms are soft bodied and/or sessile. Consequently, they have developed toxic secondary metabolites or obtained them from microorganisms to defend themselves against predators [1]. For the last 30-40 years, marine invertebrates have been an attractive research topic for scientists all over the world. A relatively small number of marine plants, animals and microbes have yielded more than 15,000 natural products including numerous compounds with potential pharmaceutical potential. Some of these have already been launched on the pharmaceutical market such as Prialt (ziconotide; potent analgesic) and Yondelis (trabectedin or ET-743; antitumor) while others have entered clinical trials, e.g., alpidin and kahalalide F. Amongst the vast array of marine natural products, the terpenoids are one of the more commonly reported and discovered to date. Sesterterpenoids (C(25)) and triterpenoids (C(30)) are of frequent occurrence, particularly in marine sponges, and they show prominent bioactivities. In this review, we survey sesterterpenoids and triterpenoids obtained from marine sponges and highlight their bioactivities.

Two new jaspamide derivatives from the marine sponge Jaspis splendens

Two new jaspamide derivatives 2 and 3, together with the parent compound jaspamide (1) have been isolated from the marine sponge Jaspis splendens collected in Kalimantan (Indonesia). The structures of the new compounds were unambiguously elucidated based on 1D and 2D NMR spectral data, mass spectrometry and comparison with jaspamide (1). The new derivatives inhibited the growth of mouse lymphoma (L5178Y) cell line in vitro with IC(50) values of <0.1 microg/mL.

Methods for isolation, purification and structural elucidation of bioactive secondary metabolites from marine invertebrates

In the past few decades, marine natural products bioprospecting has yielded a considerable number of drug candidates. Two marine natural products have recently been admitted as new drugs: Prialt (also known as ziconotide) as a potent analgesic for severe chronic pain and Yondelis (known also as trabectedin or E-743) as antitumor agent for the treatment of advanced soft tissue sarcoma. In this protocol, methods for bioactivity-guided isolation, purification and identification of secondary metabolites from marine invertebrates such as sponges, tunicates, soft corals and crinoids are discussed. To achieve this goal, solvent extraction of usually freeze-dried sample of marine organisms is performed. Next, the extract obtained is fractionated by liquid-liquid partitioning followed by various chromatographic separation techniques including thin layer chromatography, vacuum liquid chromatography, column chromatography (CC) and preparative high-performance reversed-phase liquid chromatography. Isolation of bioactive secondary metabolites is usually monitored by bioactivity assays, e.g., antioxidant (2,2-diphenyl-1-picryl hydrazyl) and cytotoxicity (microculture tetrazolium) activities that ultimately yield the active principles. Special care should be taken when performing isolation procedures adapted to the physical and chemical characteristics of the compounds isolated, particularly their lipo- or hydrophilic characters. Examples of isolation of compounds of different polarities from extracts of various marine invertebrates will be presented in this protocol. Structure elucidation is achieved using recent spectroscopic techniques, especially 2D NMR and mass spectrometry analysis.